1. Field of the Invention
The present invention relates to zeolite-based organotitanium and organochromium catalyst compositions especially suitable for the polymerization of 1-olefins such as ethylene.
2. Description of the Prior Art
Alkyltitanium and alkylchromium compounds are known to to be catalytically effective for promoting polymerization of olefins. However, many of these alkyltitanium and alkylchromium materials are stable only at very low temperatures, i.e., at temperatures of -20.degree. C. or lower when stabilizing liquids are removed. Furthermore, those of such compounds which are stable at polymerization temperatures are not capable, in and of themselves, of initiating the olefin polymerization reaction.
In order to improve stability and polymerization catalytic activity, it is known to adsorb or deposit alkyltitanium and alkylchromium materials on inorganic oxide catalyst support materials having a high surface area. Kruse; U.S. Pat. No. 3,875,132; Issued Apr. 1, 1975, and its parent Kruse; U.S. Pat. No. 3,798,250; Issued Mar. 19, 1974, for example, disclose tetraalkylchromium compounds extended on silica support materials as catalysts for the polymerization of 1-olefins. Long; U.S. Pat. Nos. 3,635,935; Issued Jan. 18, 1972; Kruse; 3,773,742; Issued Nov. 20, 1973 and Kruse; 3,712,874; Issued Jan. 23, 1973, furthermore disclose tetra(aralkyl)- and tetraneopentyl-titanium compounds which can be extended on silica support materials to form olefin polymerization catalysts.
Notwithstanding the existence of such known polymerization catalysts comprising supported organochromium and organotitanium materials, there is a continuing need to identify catalysts and catalyst support materials which can be effectively employed in the commercially important field of olefin polymerization. Accordingly, it is an object of the present invention to provide novel alkyltitanium and alkylchromium based catalyst compositions which are especially suitable for promoting polymerization of 1-olefins such as ethylene and propylene. It is a further object of the present invention to provide an olefin polymerization process employing such novel alkyltitanium and alkylchromium-based catalyst compositions.
These and other objectives can be realized by means of the composition and process embodiments of the invention described herein.